2 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 * SPDX-License-Identifier: GPL-2.0-only
8 #ifndef NOTIFICATION_THREAD_INTERNAL_H
9 #define NOTIFICATION_THREAD_INTERNAL_H
11 #include <common/compat/socket.h>
12 #include <common/credentials.h>
13 #include <common/payload.h>
14 #include <lttng/notification/channel-internal.h>
15 #include <lttng/ref-internal.h>
18 #include <urcu/rculfhash.h>
20 #include <urcu/call-rcu.h>
21 #include "notification-thread.h"
23 struct lttng_evaluation
;
24 struct notification_thread_handle
;
28 enum lttng_domain_type domain
;
37 * Hashtable containing back-refs (weak) to all channels in this session.
38 * The hashtable's key is a hash of (struct channel_key) and
39 * the value is of type (struct channel_info *).
41 struct cds_lfht
*channel_infos_ht
;
42 struct lttng_session_trigger_list
*trigger_list
;
43 /* Node in the notification thread state's sessions_ht. */
44 struct cds_lfht_node sessions_ht_node
;
46 * Weak reference to the thread state's sessions_ht. Used for removal on
49 struct cds_lfht
*sessions_ht
;
50 uint64_t consumed_data_size
;
52 /* Whether a rotation is ongoing for this session. */
54 /* Identifier of the currently ongoing rotation. */
57 /* call_rcu delayed reclaim. */
58 struct rcu_head rcu_node
;
62 struct channel_key key
;
66 * A channel info holds a reference (lttng_ref) on session_info.
67 * session_info, in return, holds a weak reference to the channel.
69 struct session_info
*session_info
;
70 /* Node in the notification thread state's channels_ht. */
71 struct cds_lfht_node channels_ht_node
;
72 /* Node in the session_info's channels_ht. */
73 struct cds_lfht_node session_info_channels_ht_node
;
74 /* call_rcu delayed reclaim. */
75 struct rcu_head rcu_node
;
79 * Facilities to carry the different notifications type in the action
80 * processing code path.
82 struct lttng_event_notifier_notification
{
83 uint64_t tracer_token
;
84 enum lttng_domain_type type
;
87 struct notification_client_list_element
{
88 struct notification_client
*client
;
89 struct cds_list_head node
;
93 * Thread safety of notification_client and notification_client_list.
95 * The notification thread (main thread) and the action executor
96 * interact through client lists. Hence, when the action executor
97 * thread looks-up the list of clients subscribed to a given
98 * condition, it will acquire a reference to the list and lock it
99 * while attempting to communicate with the various clients.
101 * It is not necessary to reference-count clients as they are guaranteed
102 * to be 'alive' if they are present in a list and that list is locked. Indeed,
103 * removing references to the client from those subscription lists is part of
104 * the work performed on destruction of a client.
106 * No provision for other access scenarios are taken into account;
107 * this is the bare minimum to make these accesses safe and the
108 * notification thread's state is _not_ "thread-safe" in any general
111 struct notification_client_list
{
112 pthread_mutex_t lock
;
114 const struct lttng_trigger
*trigger
;
115 struct cds_list_head list
;
116 /* Weak reference to container. */
117 struct cds_lfht
*notification_trigger_clients_ht
;
118 struct cds_lfht_node notification_trigger_clients_ht_node
;
119 /* call_rcu delayed reclaim. */
120 struct rcu_head rcu_node
;
123 struct notification_client
{
125 * Nests within the notification_client_list lock.
127 * Protects the outbound communication and the active flag which
128 * is used by both the notification and action executor threads.
130 * The remaining fields of the object can be used without any
131 * synchronization as they are either immutable (id, creds, version) or
132 * only accessed by the notification thread.
134 pthread_mutex_t lock
;
135 notification_client_id id
;
137 /* Client protocol version. */
138 uint8_t major
, minor
;
142 * Indicates if the credentials and versions of the client have been
147 * Conditions to which the client's notification channel is subscribed.
148 * List of struct lttng_condition_list_node. The condition member is
149 * owned by the client.
151 struct cds_list_head condition_list
;
152 struct cds_lfht_node client_socket_ht_node
;
153 struct cds_lfht_node client_id_ht_node
;
156 * If a client's communication is inactive, it means that a
157 * fatal error has occurred (could be either a protocol error or
158 * the socket API returned a fatal error). No further
159 * communication should be attempted; the client is queued for
165 * During the reception of a message, the reception
166 * buffers' "size" is set to contain the current
167 * message's complete payload.
169 struct lttng_payload payload
;
170 /* Bytes left to receive for the current message. */
171 size_t bytes_to_receive
;
172 /* FDs left to receive for the current message. */
174 /* Type of the message being received. */
175 enum lttng_notification_channel_message_type msg_type
;
177 * Indicates whether or not credentials are expected
182 * Indicates whether or not credentials were received
186 /* Only used during credentials reception. */
187 lttng_sock_cred creds
;
191 * Indicates whether or not a notification addressed to
192 * this client was dropped because a command reply was
195 * A notification is dropped whenever the buffer is not
198 bool dropped_notification
;
200 * Indicates whether or not a command reply is already
201 * buffered. In this case, it means that the client is
202 * not consuming command replies before emitting a new
203 * one. This could be caused by a protocol error or a
204 * misbehaving/malicious client.
206 bool queued_command_reply
;
207 struct lttng_payload payload
;
210 /* call_rcu delayed reclaim. */
211 struct rcu_head rcu_node
;
214 enum client_transmission_status
{
215 CLIENT_TRANSMISSION_STATUS_COMPLETE
,
216 CLIENT_TRANSMISSION_STATUS_QUEUED
,
217 /* Communication failure. */
218 CLIENT_TRANSMISSION_STATUS_FAIL
,
220 CLIENT_TRANSMISSION_STATUS_ERROR
,
224 bool notification_client_list_get(struct notification_client_list
*list
);
227 void notification_client_list_put(struct notification_client_list
*list
);
229 /* Only returns a non-zero value if a fatal error occurred. */
230 typedef int (*report_client_transmission_result_cb
)(
231 struct notification_client
*client
,
232 enum client_transmission_status status
,
236 int notification_client_list_send_evaluation(
237 struct notification_client_list
*list
,
238 const struct lttng_condition
*condition
,
239 const struct lttng_evaluation
*evaluation
,
240 const struct lttng_credentials
*trigger_creds
,
241 const struct lttng_credentials
*source_object_creds
,
242 report_client_transmission_result_cb client_report
,
246 int notification_thread_client_communication_update(
247 struct notification_thread_handle
*handle
,
248 notification_client_id id
,
249 enum client_transmission_status transmission_status
);
252 struct lttng_event_notifier_notification
*lttng_event_notifier_notification_create(
253 uint64_t tracer_token
,
254 enum lttng_domain_type domain
);
257 void lttng_event_notifier_notification_destroy(
258 struct lttng_event_notifier_notification
*event_notifier_notification
);
260 #endif /* NOTIFICATION_THREAD_INTERNAL_H */